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Chunyu Chen - One of the best experts on this subject based on the ideXlab platform.
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peptide induced bilayer thinning structure of unilamellar vesicles and the related binding behavior as revealed by x ray scattering
Biochimica et Biophysica Acta, 2013Co-Authors: User Jeng, Mingtao Lee, Kueifen Liao, Weiyu Lin, Yushan Huang, Chunyu ChenAbstract:article i nfo Article history: We have studied the bilayer thinning structure of unilamellar vesicles (ULV) of a phospholipid 1,2- dierucoyl-sn-glycero-3-phosphocholine (di22:1PC) upon binding of melittin, a water-soluble amphipathic peptide. Successive thinning of the ULV bilayers with increasing peptide concentration was monitored via small-angle X-ray scattering (SAXS). Results suggest that the two leaflets of the ULV of closed bilayers are perturbed and thinned asymmetrically upon free peptide binding, in contrast to the centro-symmetric bilayer thinning of the substrate-oriented multilamellar membranes (MLM) with premixed melittin. Moreover, thin- ning of the melittin-ULV bilayer associates closely with peptide concentration in solution and saturates at ~4%, compared to the ~8% maximum thinning observed for the correspondingly premixed peptide-MLM bi- layers. Linearly scaling the thinning of peptide-ULV bilayers to that of the corresponding peptide-MLM of a calibrated peptide-to-lipid ratio, we have deduced the number of bound peptides on the ULV bilayers as a function of free peptide concentration in solution. The hence derived X-ray-based binding isotherm allows extraction of a low binding constant of melittin to the ULV bilayers, on the basis of surface partition equilib- rium and the Gouy-Chapman Theory. Moreover, we show that the ULV and MLM bilayers of di22:1PC share a same thinning constant upon binding of a hydrophobic peptide alamethicin; this result supports the linear scaling approach used in the melittin-ULV bilayer thinning for thermodynamic binding parameters of water-soluble peptides.
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peptide induced bilayer thinning structure of unilamellar vesicles and the related binding behavior as revealed by x ray scattering
Biophysical Journal, 2013Co-Authors: Mingtao Lee, User Jeng, Kueifen Liao, Weiyu Lin, Yushan Huang, Chunyu ChenAbstract:To quantitatively correlate membrane thinning with peptide binding affinity, we have studied the bilayer thinning structure of unilamellar vesicles (ULV) of a phospholipid 1,2-dierucoyl-sn-glycero-3-phosphocholine (di22:1PC) upon binding of melittin, a water-soluble amphipathic peptide. Successive thinning of the ULV bilayers with increasing peptide concentration was monitored via small-angle X-ray scattering (SAXS). Results suggest that the two leaflets of the ULV of closed bilayers are perturbed and thinned asymmetrically upon free peptide binding, in contrast to the centro-symmetric bialyer thinning of the substrate-oriented multilamellar membranes (MLM) with premixed melittin. Moreover, thinning of the melittin-ULV bilayer saturates at ∼4 %, significantly lower than the critical thinning of ∼8% (determined via the correspondingly premixed peptide-MLM bilayers) for thermally equilibriated formation of membrane pores, revealing a critical influence of binding affinity for water soluble peptides. Scaling the peptide-ULV bilayer thinning to that of the corresponding peptide-MLM, of a calibrated peptide-to-lipid ratio, we have deduced the number of bound peptides on the ULV bilayers as a function of free peptide concentration in solution. The hence derived X-ray-based binding isotherm allows extraction of a low binding constant for melittin to the ULV bilayers, on the basis of surface partition equilibrium and the Gouy-Chapman Theory. Moreover, we show that the ULV and MLM bilayers of di22:1PC may have a same thinning constant upon binding of a same peptide, hence providing a basis in establishing X-ray-based binding isotherms for thermodynamic binding parameters of late stage peptide-membrane interactions prior to pore formation.
Joachim Seelig - One of the best experts on this subject based on the ideXlab platform.
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Protein transduction domains of HIV-1 and SIV TAT interact with charged lipid vesicles. Binding mechanism and thermodynamic analysis
Biochemistry, 2003Co-Authors: Andre Ziegler, Xiaochun Li Blatter, Anna Seelig, Joachim SeeligAbstract:Cell-penetrating peptides (CPPs) traverse cell membranes of cultured cells very efficiently by a mechanism not yet identified. Recent theories for the translocation suggest either the binding of the CPPs to extracellular glycosaminoglycans or the formation of inverted micelles with negatively charged lipids. In the present study, the binding of the protein transduction domains (PTD) of human (HIV-1) and simian immunodeficiency virus (SIV) TAT peptide (amino acid residues 47-57, electric charge z(p) = +8) to membranes containing various proportions of negatively charged lipid (POPG) is characterized. Monolayer expansion measurements demonstrate that TAT-PTD insertion between lipids requires loosely packed monolayer films. For densely packed monolayers (pi > 29 mN/m) and lipid bilayers, no insertion is possible, and binding occurs via electrostatic adsorption to the membrane surface. Light scattering experiments show an aggregation of anionic lipid vesicles when the electric surface charge is neutralized by TAT-PTD, the observed stoichiometry being close to the theoretical value of 1:8. Membrane binding was quantitated with isothermal titration calorimetry and three further methods. The reaction enthalpy is Delta H degrees approximately equal to -1.5 kcal/mol peptide and is almost temperature-independent with Delta C(p) degrees approximately 0 kcal/(mol K), indicating equal contributions of polar and hydrophobic interactions to the reaction heat capacity. The binding of TAT-PTD to the anionic membrane is described by an electrostatic attraction/chemical partition model. The electrostatic attraction energy, calculated with the Gouy-Chapman Theory, accounts for approximately 80% of the binding energy. The overall binding constant, K(app), is approximately 10(3)-10(4) M(-1). The intrinsic binding constant (K(p)), corrected for electrostatic effects and describing the partitioning of the peptide between the lipid-water interface and the membrane, is small and is K(p) approximately 1-10 M(-1). Deuterium and phosphorus-31 nuclear magnetic resonance demonstrate that the lipid bilayer remains intact upon TAT-PTD binding. The NMR data provide no evidence for nonbilayer structures and also not for domain formation. This is further supported by the absence of dye efflux from single-walled lipid vesicles. The electrostatic interaction between TAT-PTD and anionic phosphatidylglycerol is strong enough to induce a change in the headgroup conformation of the anionic lipid, indicating a short-lived but distinct correlation between the TAT-PTD and the anionic lipids on the membrane outside. TAT-PTD has a much lower affinity for lipid membranes than for glycosaminoglycans, making the latter interaction a more probable pathway for CPP binding to biological membranes.
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Magainin 2 Amide Interaction with Lipid Membranes: Calorimetric Detection of Peptide Binding and Pore Formation†
Biochemistry, 1998Co-Authors: Markus Wenk, Joachim SeeligAbstract:The interaction of the antibiotic magainin 2 amide (M2a) with lipid bilayers was investigated with high-sensitivity titration calorimetry. The enthalpy of transfer of the cationic M2a to negatively charged small unilamellar vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) (75:25, mol/mol) was measured as ΔH = −17.0 ± 1 kcal/mol of peptide. The adsorption isotherm was determined by injecting lipid vesicles into peptide solutions at low peptide concentrations ( < 7 μM). The apparent partition coefficient was Kapp ≈ 1.2 × 104 M-1 at a peptide equilibrium concentration of 1 μM but decreased with increasing peptide concentration. The hydrophobic partitioning of M2a into the lipid membrane is modulated by electrostatic effects that arise from the attraction of the positively charged peptide to the negatively charged membrane. Using the Gouy−Chapman Theory to correct for electrostatic attraction, the experimental binding iso...
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adsorption of ca2 and la3 to bilayer membranes measurement of the adsorption enthalpy and binding constant with titration calorimetry
Biochimica et Biophysica Acta, 1994Co-Authors: Renate Lehrmann, Joachim SeeligAbstract:The adsorption of Ca2+ and La3+ ions to the surface of lipid bilayer membranes was studied with high sensitivity titration calorimetry. Ca2+ adsorbs to mixed phosphatidylcholine/phosphatidylglycerol membranes with a reaction enthalpy of delta H approximately 0.1-0.2 kcal/mol. La3+ binds to sonified phosphatidylcholine vesicles with a reaction enthalpy of delta H approximately +1.8 kcal/mol. Adsorption of La3+ to phosphatidylcholine bilayers imparts a net positive charge to the membrane surface which makes the binding of further La3+ increasingly more difficult. From the decreasing amplitudes in the calorimetric titration experiment a La3+ adsorption constant of K approximately (4.1 +/- 1.1) x 10(3) M-1 was evaluated. Electrostatic effects were corrected for by means of the Gouy-Chapman Theory. The adsorption constant of Ca2+ was determined previously as K approximately 10-20 M-1 using the same binding model. Since the reaction enthalpies of Ca2+ and La3+ adsorption are endothermic, the adsorption of both metal ions to the membrane surface is driven by a distinct change in entropy.
Mingtao Lee - One of the best experts on this subject based on the ideXlab platform.
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peptide induced bilayer thinning structure of unilamellar vesicles and the related binding behavior as revealed by x ray scattering
Biochimica et Biophysica Acta, 2013Co-Authors: User Jeng, Mingtao Lee, Kueifen Liao, Weiyu Lin, Yushan Huang, Chunyu ChenAbstract:article i nfo Article history: We have studied the bilayer thinning structure of unilamellar vesicles (ULV) of a phospholipid 1,2- dierucoyl-sn-glycero-3-phosphocholine (di22:1PC) upon binding of melittin, a water-soluble amphipathic peptide. Successive thinning of the ULV bilayers with increasing peptide concentration was monitored via small-angle X-ray scattering (SAXS). Results suggest that the two leaflets of the ULV of closed bilayers are perturbed and thinned asymmetrically upon free peptide binding, in contrast to the centro-symmetric bilayer thinning of the substrate-oriented multilamellar membranes (MLM) with premixed melittin. Moreover, thin- ning of the melittin-ULV bilayer associates closely with peptide concentration in solution and saturates at ~4%, compared to the ~8% maximum thinning observed for the correspondingly premixed peptide-MLM bi- layers. Linearly scaling the thinning of peptide-ULV bilayers to that of the corresponding peptide-MLM of a calibrated peptide-to-lipid ratio, we have deduced the number of bound peptides on the ULV bilayers as a function of free peptide concentration in solution. The hence derived X-ray-based binding isotherm allows extraction of a low binding constant of melittin to the ULV bilayers, on the basis of surface partition equilib- rium and the Gouy-Chapman Theory. Moreover, we show that the ULV and MLM bilayers of di22:1PC share a same thinning constant upon binding of a hydrophobic peptide alamethicin; this result supports the linear scaling approach used in the melittin-ULV bilayer thinning for thermodynamic binding parameters of water-soluble peptides.
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peptide induced bilayer thinning structure of unilamellar vesicles and the related binding behavior as revealed by x ray scattering
Biophysical Journal, 2013Co-Authors: Mingtao Lee, User Jeng, Kueifen Liao, Weiyu Lin, Yushan Huang, Chunyu ChenAbstract:To quantitatively correlate membrane thinning with peptide binding affinity, we have studied the bilayer thinning structure of unilamellar vesicles (ULV) of a phospholipid 1,2-dierucoyl-sn-glycero-3-phosphocholine (di22:1PC) upon binding of melittin, a water-soluble amphipathic peptide. Successive thinning of the ULV bilayers with increasing peptide concentration was monitored via small-angle X-ray scattering (SAXS). Results suggest that the two leaflets of the ULV of closed bilayers are perturbed and thinned asymmetrically upon free peptide binding, in contrast to the centro-symmetric bialyer thinning of the substrate-oriented multilamellar membranes (MLM) with premixed melittin. Moreover, thinning of the melittin-ULV bilayer saturates at ∼4 %, significantly lower than the critical thinning of ∼8% (determined via the correspondingly premixed peptide-MLM bilayers) for thermally equilibriated formation of membrane pores, revealing a critical influence of binding affinity for water soluble peptides. Scaling the peptide-ULV bilayer thinning to that of the corresponding peptide-MLM, of a calibrated peptide-to-lipid ratio, we have deduced the number of bound peptides on the ULV bilayers as a function of free peptide concentration in solution. The hence derived X-ray-based binding isotherm allows extraction of a low binding constant for melittin to the ULV bilayers, on the basis of surface partition equilibrium and the Gouy-Chapman Theory. Moreover, we show that the ULV and MLM bilayers of di22:1PC may have a same thinning constant upon binding of a same peptide, hence providing a basis in establishing X-ray-based binding isotherms for thermodynamic binding parameters of late stage peptide-membrane interactions prior to pore formation.
User Jeng - One of the best experts on this subject based on the ideXlab platform.
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peptide induced bilayer thinning structure of unilamellar vesicles and the related binding behavior as revealed by x ray scattering
Biochimica et Biophysica Acta, 2013Co-Authors: User Jeng, Mingtao Lee, Kueifen Liao, Weiyu Lin, Yushan Huang, Chunyu ChenAbstract:article i nfo Article history: We have studied the bilayer thinning structure of unilamellar vesicles (ULV) of a phospholipid 1,2- dierucoyl-sn-glycero-3-phosphocholine (di22:1PC) upon binding of melittin, a water-soluble amphipathic peptide. Successive thinning of the ULV bilayers with increasing peptide concentration was monitored via small-angle X-ray scattering (SAXS). Results suggest that the two leaflets of the ULV of closed bilayers are perturbed and thinned asymmetrically upon free peptide binding, in contrast to the centro-symmetric bilayer thinning of the substrate-oriented multilamellar membranes (MLM) with premixed melittin. Moreover, thin- ning of the melittin-ULV bilayer associates closely with peptide concentration in solution and saturates at ~4%, compared to the ~8% maximum thinning observed for the correspondingly premixed peptide-MLM bi- layers. Linearly scaling the thinning of peptide-ULV bilayers to that of the corresponding peptide-MLM of a calibrated peptide-to-lipid ratio, we have deduced the number of bound peptides on the ULV bilayers as a function of free peptide concentration in solution. The hence derived X-ray-based binding isotherm allows extraction of a low binding constant of melittin to the ULV bilayers, on the basis of surface partition equilib- rium and the Gouy-Chapman Theory. Moreover, we show that the ULV and MLM bilayers of di22:1PC share a same thinning constant upon binding of a hydrophobic peptide alamethicin; this result supports the linear scaling approach used in the melittin-ULV bilayer thinning for thermodynamic binding parameters of water-soluble peptides.
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peptide induced bilayer thinning structure of unilamellar vesicles and the related binding behavior as revealed by x ray scattering
Biophysical Journal, 2013Co-Authors: Mingtao Lee, User Jeng, Kueifen Liao, Weiyu Lin, Yushan Huang, Chunyu ChenAbstract:To quantitatively correlate membrane thinning with peptide binding affinity, we have studied the bilayer thinning structure of unilamellar vesicles (ULV) of a phospholipid 1,2-dierucoyl-sn-glycero-3-phosphocholine (di22:1PC) upon binding of melittin, a water-soluble amphipathic peptide. Successive thinning of the ULV bilayers with increasing peptide concentration was monitored via small-angle X-ray scattering (SAXS). Results suggest that the two leaflets of the ULV of closed bilayers are perturbed and thinned asymmetrically upon free peptide binding, in contrast to the centro-symmetric bialyer thinning of the substrate-oriented multilamellar membranes (MLM) with premixed melittin. Moreover, thinning of the melittin-ULV bilayer saturates at ∼4 %, significantly lower than the critical thinning of ∼8% (determined via the correspondingly premixed peptide-MLM bilayers) for thermally equilibriated formation of membrane pores, revealing a critical influence of binding affinity for water soluble peptides. Scaling the peptide-ULV bilayer thinning to that of the corresponding peptide-MLM, of a calibrated peptide-to-lipid ratio, we have deduced the number of bound peptides on the ULV bilayers as a function of free peptide concentration in solution. The hence derived X-ray-based binding isotherm allows extraction of a low binding constant for melittin to the ULV bilayers, on the basis of surface partition equilibrium and the Gouy-Chapman Theory. Moreover, we show that the ULV and MLM bilayers of di22:1PC may have a same thinning constant upon binding of a same peptide, hence providing a basis in establishing X-ray-based binding isotherms for thermodynamic binding parameters of late stage peptide-membrane interactions prior to pore formation.
Weiyu Lin - One of the best experts on this subject based on the ideXlab platform.
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peptide induced bilayer thinning structure of unilamellar vesicles and the related binding behavior as revealed by x ray scattering
Biochimica et Biophysica Acta, 2013Co-Authors: User Jeng, Mingtao Lee, Kueifen Liao, Weiyu Lin, Yushan Huang, Chunyu ChenAbstract:article i nfo Article history: We have studied the bilayer thinning structure of unilamellar vesicles (ULV) of a phospholipid 1,2- dierucoyl-sn-glycero-3-phosphocholine (di22:1PC) upon binding of melittin, a water-soluble amphipathic peptide. Successive thinning of the ULV bilayers with increasing peptide concentration was monitored via small-angle X-ray scattering (SAXS). Results suggest that the two leaflets of the ULV of closed bilayers are perturbed and thinned asymmetrically upon free peptide binding, in contrast to the centro-symmetric bilayer thinning of the substrate-oriented multilamellar membranes (MLM) with premixed melittin. Moreover, thin- ning of the melittin-ULV bilayer associates closely with peptide concentration in solution and saturates at ~4%, compared to the ~8% maximum thinning observed for the correspondingly premixed peptide-MLM bi- layers. Linearly scaling the thinning of peptide-ULV bilayers to that of the corresponding peptide-MLM of a calibrated peptide-to-lipid ratio, we have deduced the number of bound peptides on the ULV bilayers as a function of free peptide concentration in solution. The hence derived X-ray-based binding isotherm allows extraction of a low binding constant of melittin to the ULV bilayers, on the basis of surface partition equilib- rium and the Gouy-Chapman Theory. Moreover, we show that the ULV and MLM bilayers of di22:1PC share a same thinning constant upon binding of a hydrophobic peptide alamethicin; this result supports the linear scaling approach used in the melittin-ULV bilayer thinning for thermodynamic binding parameters of water-soluble peptides.
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peptide induced bilayer thinning structure of unilamellar vesicles and the related binding behavior as revealed by x ray scattering
Biophysical Journal, 2013Co-Authors: Mingtao Lee, User Jeng, Kueifen Liao, Weiyu Lin, Yushan Huang, Chunyu ChenAbstract:To quantitatively correlate membrane thinning with peptide binding affinity, we have studied the bilayer thinning structure of unilamellar vesicles (ULV) of a phospholipid 1,2-dierucoyl-sn-glycero-3-phosphocholine (di22:1PC) upon binding of melittin, a water-soluble amphipathic peptide. Successive thinning of the ULV bilayers with increasing peptide concentration was monitored via small-angle X-ray scattering (SAXS). Results suggest that the two leaflets of the ULV of closed bilayers are perturbed and thinned asymmetrically upon free peptide binding, in contrast to the centro-symmetric bialyer thinning of the substrate-oriented multilamellar membranes (MLM) with premixed melittin. Moreover, thinning of the melittin-ULV bilayer saturates at ∼4 %, significantly lower than the critical thinning of ∼8% (determined via the correspondingly premixed peptide-MLM bilayers) for thermally equilibriated formation of membrane pores, revealing a critical influence of binding affinity for water soluble peptides. Scaling the peptide-ULV bilayer thinning to that of the corresponding peptide-MLM, of a calibrated peptide-to-lipid ratio, we have deduced the number of bound peptides on the ULV bilayers as a function of free peptide concentration in solution. The hence derived X-ray-based binding isotherm allows extraction of a low binding constant for melittin to the ULV bilayers, on the basis of surface partition equilibrium and the Gouy-Chapman Theory. Moreover, we show that the ULV and MLM bilayers of di22:1PC may have a same thinning constant upon binding of a same peptide, hence providing a basis in establishing X-ray-based binding isotherms for thermodynamic binding parameters of late stage peptide-membrane interactions prior to pore formation.
